The Art of “Blending” – Winter Camouflage (November Study 1)

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What is Camouflage?

cam·ou·flage

  1. concealment of things: concealment of things, by disguising them to look like their surroundings
  2. concealing devices: devices designed to conceal by imitating the colors of the surrounding environment
  3. protective coloration in animals: the devices that animals use to blend into their environment in order to avoid being seen by predators or prey, especially coloration

Fall provides many opportunities to observe how living things prepare themselves for winter. One topic we will explore this month is how animals’ coloration can aid in their protection during the fall and winter months.

This article will focus specifically on how animals’ coloration protects them in the fall and winter months. The larger topic of coloration will be reserved for another month.

Types of Camouflage

Animals exhibit several types of coloration, each of which protects them from harm in a different way.

  1. Concealing Coloration
  2. Disguise
  3. Disruptive Coloration
  4. Mimicry
  5. No Camouflage

Each of these methods will be examined more closely as it applies to fall and winter protection.

Concealing Coloration

When folks think of camouflage, this is the type of camouflage that probably comes to mind first, and is probably one of the most common, especially among prey species of birds, insects and other prey animals.

When an animal exhibits concealing coloration, it is colored or patterned in such a way that it blends into its surroundings, looking very similar to its environment.

Many animals adopt a different coloration in the winter. Some adopt the drab browns and grays of the fall and winter woodlands, such as many sparrows, winter goldfinches, and winter starlings.

Here’s a fun birding note – there are so many small birds that move fast, hide undercover, and are hard to tell apart unless you get a good look at them through binoculars: warblers, sparrows, finches, buntings… birders refer to these as “little brown jobs” or “LBJs.”

 

Camouflage Concealing Color Fall Nature Study

Many sparrows and other small birds use concealing color year-round, or just in the winter, to hide among the brown leaves of the forest floor. See “Little Brown Birds: Sparrows and Friends” for a study of brown birds. (c) Kim M. Bennett, 2010.

 

Disguise

Overwintering insects are at great risk of being someone’s wintertime food. In many cases, they disguise themselves as dead leaves or twigs, to avoid being noticed. This is the case with many of the giant silk moths, whose caterpillars overwinter in cocoons wrapped in dead leaves and twigs, effectively blending them into the leaf litter. This is even more important, when you consider that some, such as the Luna moth, must overwinter, then remain in the pupa until nearly the end of July, before the adult moth emerges – a long time to remain hidden from view, and from potential predators.

 

Camouflage Fall Nature Study

Many caterpillars cover their cocoons with dead leaves, to look like leaf litter, as they overwinter. (c) Kim M. Bennett, 2012.

 

Disruptive Coloration

In the fall and winter, some birds don’t change color drastically, but become a little more striped or spotted, and begin to congregate in large groups. The combination of the markings and the masses of birds make it hard for a potential predator to pick one bird out of the group, similar to the way that the stripes on zebras make it hard for a lion to pick one zebra out of the herd.

This type of camouflage is called disruptive coloration. By adopting a pattern of stripes or spots, the “edges” of the animal become less distinct, making it hard for a predator to zero in on one animal, or on an animal’s vulnerable spot (head, neck). Gathering in a large group makes this even more effective.

European starlings don’t change color dramatically, but, in the winter, become much more spotted. Similarly, juncos have a strikingly white belly that blends in with the snow, making them look like a cluster of black dots hopping over the snow.

 

Disruptive Coloration Nature Study Fall

Juncos’ white underparts blend in with the snow, making their vulnerable underside indistinguishable from their environment. (c) Phoenix Wolf-Ray, 2008 via Creative Commons.

 

Mimicry

Sometimes, animals have markings that resemble other, less “edible” or more dangerous creatures. The Viceroy and monarch butterflies are a classic example of this, as are caterpillars that have markings and “horns” to resemble more menacing creatures. While not a true mimicry, there is a subtle version of this “look-alike” phenomenon seen in winter birds.

If you have been watching your feeding station (that you assembled last month), you may have noticed a few days when you had huge flocks of black birds that descended on the feeders, stayed for an hour or so, then left as quickly as they arrived. This happens in my feeding area sometime in September or October. I usually see a huge flock of grackles, but, amongst the grackles, there will be a few starlings, some red-winged blackbirds, and maybe a crow or two.

While this isn’t true mimicry, the species that are in fewer numbers gain protection from looking like, and joining, the flock of grackles (a species that commonly gathers in large numbers in the fall). This association doesn’t affect the grackles, but benefits the other bird species. Would-be predators are less likely to attack the raucous grackles than they are the more timid starlings and blackbirds. So there is protection by association.

 

camouflage fall nature study

Birds such as red-winged blackbirds and starlings, will sometimes join large flocks of similarly colored birds, such as these grackles, for safety in numbers. (c) Rich Anderson, 2005 via Creative Commons.

 

No Camouflage

Not every animal uses camouflage as a protective measure, in winter or any other time of the year. Just one look at your bird list from your bird feeding station, and you can see a number of common species that remain brightly colored, year round:

  • Northern Cardinal
  • Blue Jay
  • Eastern Bluebird
  • Evening Grosbeak

There are also some common feeder birds that are brightly colored, but migrate to warmer, or even tropical, regions during the winter, so they continue to blend in with “summery” surroundings:

  • Scarlet Tanagers
  • Northern Orioles
  • Many warblers
  • Rose-breasted Grosbeak

For these birds, the advantage of bright colors to attract a mate outweighs the risk of being easy to spot, or the bird has other means to protect itself from predators.

 

Blue Jay No Camouflage

Blue jays keep their bright blue coloration year-round. (c) Kim M. Bennett, 2010.

 

The Learning Task

The Key skills and concepts

  • Dimension 1: Science ProcessEngaging in Argument from Evidence
  • Dimension 2: Cross-Cutting ConceptCause-and-Effect: Mechanism and Explanation
  • Dimension 3: Scientific DisciplinesLife Sciences: Biological Evolution – Unity and Diversity
  • Cognitive Process: Comparing & Contrasting

If you are not a member of Project Feeder Watch, consider donating your time (and a few dollars) to become a citizen scientist, and contribute your observations to a scientific project. For your subscription, you’ll get a poster of common feeder birds in North America, data sheets and/or access to electronic recording forms online, and a subscription to a monthly newsletter that is chock full of great information for homeschool, birding enthusiasts or classroom use.

If you’re not a member, you can use this procedure to study the fall and winter coloration of your feeder birds:

  1. Find a place to observe birds for about 15-30 minutes. [Your bird feeding station is a good place]. It is good to pick the same time each week, so that you get a true representation of the kinds of birds that come to your feeder.
  2. Print out copies of the camouflage recording sheet (enough for pairs or small groups of students).
  3. Note the date and weather conditions or any other important factors that might affect bird numbers (e.g., disturbances in the environment; a new feeder or food; the presence of a dog or cat in the area).
  4. Record the species of birds that come to your feeder during this time in the first column.
  5. Record the maximum number of that bird that you see at any one time (use a pencil so you can erase).
  6. Check off what kind(s) of camouflage you think the species uses in the next columns (NOTE: Only the most common winter camouflage types are listed).
  7. Record any other interesting observations in the last column.
  8. Summarize your observations about birds and coloration on the lines at the bottom of the page.

NOTE: There are no right answers to this task. The point is to begin to examine the coloration of birds, compare them, and draw some inferences about the relationship between the birds’ coloration and adaptation to changing seasons.

 

Share

Post your observations, photos and links to your blog post to the November edition of the Simple Science Blog Carnival! Make sure you include a link back to this post or the blog carnival in your blog post.

 

Backyard Birds of North America: An Introduction to Familiar Species — Perfect for bird lovers, this informative pamphlet details more than 140 urban avian species and provides instructions on attracting and feeding backyard birds. Laminated for durability, this handy guide is ideal for field use by novices and experts alike. $2.71, Barnes & Noble.

 

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